The background of the invention will be discussed in two parts:
1. Field of the Invention
This invention relates to devices for use in connection with construction, and more particularly to devices for use as spacers for reinforcing rods in reinforced concrete construction.
2. Description of the Prior Art
In construction applications, spacers and retainers are utilized in varying degrees for captively retaining such devices as water and gas tubing as well as wiring cabling or harnesses. In addition, with construction involving reinforced concrete, such as highways, or in the floors, or in the walls of buildings, spacers devices are required for supporting and maintaining reinforcing rods or bars which are positioned in the area where the concrete is to be poured. These rods are sometimes referred to as "rebars". Depending on such parameters as the total surface area and the thickness of the end product of concrete, reinforcement is mandated in varying degrees by builidng codes. One such method of reinforcement involves a steel mesh, while in major concrete construction, such as highways, and for high-rise buildings, reinforcing rods of various diameters, typically one half inch or more, are required. In addition, on such jobs, the reinforcing bars may be positioned in spaced layers due to the thickness of the floor, for example. After the reinforcing bars or latticework is prepared, the concrete is then poured over this framework, which is ultimately embedded within the highway, floor or wall.
By way of example, for a concrete floor on a prepared surface, spacers are needed for providing the vertical separation from the ground, with other spacers connected between layers of rebars. The prepared surface is generally a compacted surface, which may be provided with a layer of compacted sand, with a plastic sheet covering thereon providing a moisture barrier. Spacers are positioned on the prepared surface for supporting the rebars in a plane generally parallel to the prepared surface. Typically, with modern building codes, a spacer is needed every foot of the rebar, with spacing between parallel rebars of about one foot.
Prior art spacers include a pair of generally identically configured rectangular plate members having a height equal to the spacing needed. Each plate includes a longitudinally extending slot of a width generally equal to the width of the plate member. the slots are engaged to form a spacer of cruciform cross-section. One or both of the plates will have at least one hole extending therethrough for receiving a piece of wire which is passed through the hole and about the rebar resting on the spacer, the wire then being twisted to secure the rebar on the spacer.
Some of the difficulties encountered with such spacers involved rusting or decomposition, since the spacers were primarily metallic. In addition with an edge on top of the spacer, such spacers had a tendency to tip after assembly or cock at an angle, thereby defeating the preferable parallel relation of the rebar to the ground or to other rebars at that point of tipping, with consequent loss of strength of the concrete at that location.
Other prior art spacers were formed of plastic, such as of the two piece slotted plate construction, or of a one piece molded construction with the cruciform cross-section. While the problem of rusting was eliminated, the problem of stability and integrity was not.
Accordingly it is an object of the present invention to provide a new and improved spacer for use in construction applications.
It is another object of the present invention to provide a new and improved spacer, particularly adapted for use with reinforcing rods in a single layer or in multiple layers in reinforced concrete construction.
It is a further object of the present invention to provide a new and improved spacer device which may be formed of one piece or a plurality of pieces with a saddle portion for receiving the rebar thereon.